Henry Willoughby Mann (18 July 1873 – 4 October 1952) was an Australian police officer and politician who was a Nationalist Party member of the Legislative Assembly of Western Australia from 1921 to 1933, representing the seat of Perth.
By his retirement in 1920, Mann had reached the rank of detective inspector and served as the chief of the Criminal Investigations Branch (CIB).
[1] At the 1921 state election, Mann won the seat of Perth as a Nationalist candidate, replacing the retiring Robert Pilkington.
He was re-elected on another three occasions, but was defeated by the Labor Party's Ted Needham at the 1933 election.
[2] In 1940, he stood for the Legislative Council as an independent, but was defeated by Hubert Parker in Metropolitan-Suburban Province.